Nearly all mechanical motions of a machine create potential hazards to the operator. Examples of movements which create such hazards include punching, shearing, bending, meshing gears, cutting, and rotating parts. All of these potential hazards can be eliminated or minimized by a properly designed and placed guarding mechanism. Barrier guards are typically designed and placed to allow for proper machine function while simultaneously inhibiting the entry of body parts (fingers). This is typically done by placing the guard at a specified distance from the hazard zone and limiting the opening size so that the body part cannot enter into this area of the machine. A common example can be viewed by examining any small portable household fan. The guarding enclosure is open to air, yet the openings cannot be penetrated deeply enough so that the rotating element of the fan contacts the body part. Hence, the size of the opening and distance from the hazard zone define effective guard design and placement.